The wiper blades that reach the spare parts market must be packaged, for various reasons. Primarily this is to protect the vulnerable wiper edges, located on the wiper lips of the rubber-elastic wiper blade strips, which have to perform the precision work in wiping motor vehicle windows. Conventional wiper blades in which the wiper blade strip is retained by a support bracket frame (German patent disclosure DE 15 05 397) are accommodated loosely in packing units known as blister packs. Because the straightened-out wiper blade is wrapped loosely and thus without tension, satisfactory protection as well as good sales presentation of such wiper blade are achieved. In addition, the size of a packing unit can also be adapted to the size of the wiper blade such that the space required for the packing unit can be kept as small as possible.
Wiper blades with an elongated spring-elastic support element for the wiper strip (German patent disclosures DE 196 41 042 A1 and DE 197 29 864 A1) must be curved in the unstressed statexe2x80x94that is, the way in which they reach the marketxe2x80x94in such a way that during wiper operation, proper contact of the wiper lip over the entire length of the wiper blade is assured, even for spherically curved motor vehicles. This precurvature of the wiper blade means that it takes up considerable space, if it is to be accommodated loosely in a known packing unit. Straightening out the wiper blade in a narrow packing unit would mean that because the support element is now stressed, the wiper lip would be constantly pressed with its wiping edges against an inner wall of the packing unit. This would lead to deformation of the wiper lip and thus make the wiper blade unusable.
The straightened-out, channel-like packing unit surrounds the wiper lip with spacing over the entire length of the wiper lip. The bracing means disposed on the longitudinal channel edges rest on the supports of the wiper blade in such a way that the wiper blade on being introduced into the packing unit is straightened from its unstressed, curved shape in a space-saving way to match the straightening out of the packing unit and is fixed in this straightened-out position by its own rigidity, without thereby putting stress on the wiper lip. The disposition of the wiper blade supports on both sides of the longitudinal plane of symmetryxe2x80x94which is oriented transversely to the band faces of the support elementxe2x80x94prevents the packaged wiper blade from becoming curved in the direction of the support element band faces. Straightening out the wiper blade has no adverse effects on its later use, because this straightening out is no greater than the straightening out during wiper operation that is dictated by the shape of the window to be wiped.
In certain applications, in a first embodiment of the invention it can be advantageous if the support element protrudes in a least some portions past the wiper strip with at least two lateral peripheral portions disposed opposite one another relative to the planexe2x80x94which in most cases is a plane of symmetryxe2x80x94on which peripheral portions the supports of the wiper blade are embodied, and if furthermore extensions of U-shaped cross section associated with the supports of the wiper blade are disposed on each of the longitudinal channel edges of the packing unit, the respective legs of which U, gripping the peripheral portions of the support element, extend toward the plane of symmetry. The sides facing one another of the legs of the U form the bracing means, which cooperated with band faces, usable as supports, of the support element that face away from one another. The U-shaped, rectilinearly straightened-out extensions of the packing unit force the wiper blade to undergo the straightening out when the wiper blade is introduced in the longitudinal direction into the packing unit.
Another applicationxe2x80x94for instance when the support element does not protrude laterally past the wiper stripxe2x80x94provides that the wiper strip of the wiper blade is provided on each of its two opposed long sides with a respective longitudinal groove, open toward its respective long side,.on the side faces of which the supports toward the wiper blade are embodied, and that furthermore, on each of the longitudinal channel edges, a respective clawlike extension is embodied, which extends toward the plane of symmetry into the particular longitudinal groove associated with it. The two clawlike extensions of the packing unit form its bracing means, which cooperate with groove walls, facing one another of the wiper strip that form the bracing means when the packing unit is slipped onto the wiper strip of the wiper blade and in the process is straightened out.
An especially simple, economical version of the invention is obtained if the wiper strip has a head strip, which is joined to the support element and via a rib remaining between the two longitudinal grooves is joined to the striplike wiper lip, and the supports of the wiper blade are embodied on the side walls of the two longitudinal grooves. Embodying the rib by the provision of the two longitudinal grooves is the current practice, and so these can be used for the packing unit.
Regardless of this, it can be expedient, for instance for the sake of stability, if the supports toward the wiper blade are embodied on longitudinal grooves disposed in the head strip.
A refinement of the invention provides that the packing unit has two joined-together channel-like components, whose respective supports point in opposite direction relative to a plane laid through the packing unit. As a result, it is attained that the forces exerted on the packing unit by the two straightened-out wiper blades located in the packing unit cancel one another out, because they are oriented contrary to one another. The dimensions of the walls of the packing unit can therefore be reduced.
Depending on the demands made of the thus-formed double packing unit in terms of its dimensions, it is an attractive option either to join the two components together along their channel bases, or to embody the packing unit such that its two components, over at least a portion thereof, have a common channel cheek.
Simple manufacture of the packing unitxe2x80x94for instance by endless extrusionxe2x80x94and simple manipulation on inserting the wiper blades into the packing unit are obtained if the channel-like component is open on both of its ends.
If the wiper blade, on the band face of the support element remote from the wiper lip, is provided, with a spoiler strip extending in the longitudinal direction of the wiper blade, protection for this spoiler strip is gained if the packing unit, on its side remote from the channel base, has a hood fitting over the spoiler strip.
Economical production of the packing unit is obtained if the packing unit is made from a plastic.